在研究傳統家用燃氣報警器的基礎上，以ZigBee協議為平臺，構建mesh網狀網絡實現網絡化的智能語音報警系統。由于傳感器本身的溫度和實際環境溫度的影響，傳感器標定后采用軟件補償方法。為了減少系統費用，前端節點采用半功能節點設備，路由器和協調器采用全功能節點設備，構建mesh網絡所形成的家庭內部報警系統，通過通用的電話接口連接到外部的公用電話網絡，啟動語音模塊進行報警。實驗結果表明，在2.4 GHz頻率下傳輸，有墻等障礙物的情況下，節點的傳輸距離大約為35 m，能夠滿足家庭需要，且系統工作穩定，但在功耗方面仍需進一步改善。
Abstract:
On the basis of studying traditional household gas alarm system, this paper proposed the platform for the ZigBee protocol，and constructed mesh network to achieve network-based intelligent voice alarm system. Because of the sensor temperature and the actual environment temperature, this system design used software compensation after calibrating sensor. In order to reduce system cost, semi-functional node devices were used as front-end node, however, full-function devices were used as routers and coordinator，constructed alarm system within the family by building mesh network，connected to the external public telephone network through the common telephone interface, started the voice alarm module. The results indicate that nodes transmit about 35m in the distance in case of walls and other obstacles by 2.4GHz frequency transmission, this is able to meet family needs and work steadily, but still needs further improvement in power consumption.
This example shows how to update at regulate period the WWDG counter using theEarly Wakeup interrupt (EWI).
The WWDG timeout is set to 262ms, refresh window set to 41h and the EWI isenabled. When the WWDG counter reaches 40h the EWI is generated and in the WWDGISR the counter is refreshed to prevent a WWDG reset and led connected to PC.07is toggled.The EXTI line9 is connected to PB.09 pin and configured to generate an interrupton falling edge.In the NVIC, EXTI line9 to 5 interrupt vector is enabled with priority equal to 0and the WWDG interrupt vector is enabled with priority equal to 1 (EXTI IT > WWDG IT).
The EXTI Line9 will be used to simulate a software failure: once the EXTI line9event occurs (by pressing Key push-button on EVAL board) the correspondent interruptis served, in the ISR the led connected to PC.07 is turned off and the EXTI line9pending bit is not cleared. So the CPU will execute indefinitely EXTI line9 ISR andthe WWDG ISR will never be entered(WWDG counter not updated). As result, when theWWDG counter falls to 3Fh the WWDG reset occurs.If the EXTI line9 event don抰 occurs the WWDG counter is indefinitely refreshed inthe WWDG ISR which prevent from WWDG reset.
If the WWDG reset is generated, after resuming from reset a led connected to PC.06is turned on.
In this example the system is clocked by the HSE(8MHz).
MAXQUSBJTAGOW評估板軟件:關鍵特性 Easily Load and Debug Code Interface Provides In-Application Debugging Features Step-by-Step Execution Tracing Breakpointing by Code Address, Data Memory Address, or Register Access Data Memory View and Edit Supports Logic Levels from 1.1V to 3.6V Supports JTAG and 1-Wire Protocols Each Adapter Has Its Own Unique Serial ID, Allowing Multiple Adapters to be connected Without COM Port Conflicts Has In-Field Upgradable Capability if Firmware Needs to be Upgraded Enclosure Protects from Shorts and ESD
MAXQUSBJTAGOW評估板軟件:關鍵特性 Easily Load and Debug Code Interface Provides In-Application Debugging Features Step-by-Step Execution Tracing Breakpointing by Code Address, Data Memory Address, or Register Access Data Memory View and Edit Supports Logic Levels from 1.1V to 3.6V Supports JTAG and 1-Wire Protocols Each Adapter Has Its Own Unique Serial ID, Allowing Multiple Adapters to be connected Without COM Port Conflicts Has In-Field Upgradable Capability if Firmware Needs to be Upgraded Enclosure Protects from Shorts and ESD
Abstract: Designers who must interface 1-Wire temperature sensors with Xilinx field-programmable gate arrays(FPGAs) can use this reference design to drive a DS28EA00 1-Wire slave device. The downloadable softwarementioned in this document can also be used as a starting point to connect other 1-Wire slave devices. The systemimplements a 1-Wire master connected to a UART and outputs temperature to a PC from the DS28EA00 temperaturesensor. In addition, high/low alarm outputs are displayed from the DS28EA00 PIO pins using LEDs.
Abstract: As industrial control systems (ICSs) have become increasingly connected and use more off-the-shelfcomponents, new vulnerabilities to cyber attacks have emerged. This tutorial looks at three types of ICSs:programmable logic controllers (PLCs), supervisory control and data acquisition (SCADA) systems, anddistributed control systems (DCSs), and then discusses security issues and remedies. This document alsoexplains the benefits and limitations of two cryptographic solutions (digital signatures and encryption) andelaborates on the reasons for using security ICs in an ICS to support cryptography.
Automobiles, aircraft, marine vehicles, uninterruptiblepower supplies and telecom hardware represent areasutilizing series connected battery stacks. These stacksof individual cells may contain many units, reaching potentialsof hundreds of volts. In such systems it is oftendesirable to accurately determine each individual cell’svoltage. Obtaining this information in the presence of thehigh “common mode” voltage generated by the batterystack is more diffi cult than might be supposed.
The traffic light is timed and lets cars pass during a
specific time period. There is a pedestrial crossing
button that lets pedestrians cross. The lights are
connected to Port 1. You can see this in action using
dScope.
LPC2148 USB Audio Device Example
This USB example project implements an USB Audio Device that connects via the USB interface to the PC. It may be used on the following devices:
LPC2141
LPC2142
LPC2144
LPC2146
LPC2148
An USB Audio Device (HID) does not require any special USB driver, since the USB Audio support is already built into Windows 2000 and Windows XP. Therefore USB Audio devices can be directly connected to the computer. This example project is designed to work with Keil MCB2140 Evaluation Board.
Refer to Running USBAudio for information on how to operate this example project.
Linphone is a web phone: it let you phone to your friends anywhere in the whole world, freely, simply by using the internet. The cost of the phone call is the cost that you spend connected to the internet.
